GPS-coupled contaminant monitors on free-ranging Chernobyl wolves challenge a fundamental assumption in exposure assessments

• Published in: Environment International
• Main Authors: Hinton, Thomas, G, Byrne, Michael, E, Webster, Sarah, C, Love, Cara, N, Broggio, David, Trompier, Francois, Shamovich, Dmitry, Horloogin, Sergay, Lance, Stacey, L, Brown, Justin, Dowdall, Mark, Beasley, James, C
• Other Authors: Fukushima University Fukushima, Japan, University of Technology Sydney (UTS), Dept Food Environm & Rural Affairs Defra, Partenaires INRAE, Savannah River Ecology Laboratory (SREL), University of Georgia USA, Laboratoire d'évaluation de la dose interne (IRSN/PSE-SANTE/SDOS/LEDI), Service de dosimétrie (IRSN/PSE-SANTE/SDOS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire de dosimétrie des rayonnements ionisants (IRSN/PSE-SANTE/SDOS/LDRI), Norwegian Radiation and Nuclear Safety Authority, Warnell School of Forestry and Natural Resources
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: Chernobyl Wolves Environmental risk assessment Model verification External exposure Radiation dose; [SDE]Environmental Sciences; Canis lupus
• Online Access: https://hal.science/hal-04021014; https://hal.science/hal-04021014/document; https://hal.science/hal-04021014/file/1-s2.0-S0160412019323700-main.pdf; https://doi.org/10.1016/j.envint.2019.105152

International audience Measurements of external contaminant exposures on individual wildlife are rare because of difficulties in using contaminant monitors on free-ranging animals. Most wildlife contaminant exposure data are therefore simulated with computer models. Rarely are empirical exposure data available to verify model simulations, or to test fundamental assumptions inherent in exposure assessments. We used GPS-coupled contaminant monitors to quantify external exposures to individual wolves (Canis lupus) living within the Belarus portion of Chernobyl's 30-km exclusion zone. The study provided data on animal location and contaminant exposure every 35 min for 6 months, resulting in ~6600 individual locations and 137 Cs external exposure readings per wolf, representing the most robust external exposure data published to date on free ranging animals. The data provided information on variation in external exposure for each animal over time, as well as variation in external exposure among the eight wolves across the landscape of Chernobyl. The exposure data were then used to test a fundamental assumption in screening-level risk assessments, espoused in guidance documents of the U.S. Environmental Protection Agency and U.S. Department of Energy,-Mean contaminant concentrations conservatively estimate individual external exposures. We tested this assumption by comparing our empirical data to a series of simulations using the ERICA modeling tool. We found that modeled simulations of mean external exposure (10.5 mGy y −1), based on various measures of central tendency, under-predicted mean exposures measured on five of the eight wolves wearing GPS-contaminant monitors (i.e., 12.3, 26.3, 28.0, 28.8 and 35.7 mGy y −1). If under-prediction of exposure occurs for some animals, then arguably the use of averaged contaminant concentrations to predict external exposure is not as conservative as proposed by current risk assessment guidance. Thus, a risk assessor's interpretation of simulated exposures in a screening-level ...